Abstract: An IR transmitting and receiving device with a signal communicator has an RF transmitter unit connected to an IR receiver and an RF receiver communicating with the RF transmitter unit. The RF receiver is able to get the status of the signal at the IR receiver through the RF transmitter unit and then show the status on a display device. Therefore when a user sets the IR transmitting and receiving device, the user easily adjusts one position of the IR transmitter and the IR receiver, until the IR receiver received the max light strength from the IR transmitter.

Abstract: A system, method and apparatus for establishing a secure wireless radio communications link between two devices that minimizes the exposure of sensitive information to third party interception is disclosed. The secure link is established by first establishing an infrared link between the two devices for the exchange of sensitive information, such as encryption information. Subsequent communications would then have the benefit of encryption protection, establishing the secure wireless radio communications link.

Abstract: A Fiber-wireless uplink consists of a wireless channel followed by a radio-over-fiber (ROF) link. Typically, nonlinear distortion of the ROF link is the major concern when the radio frequency is only a few GHz. This especially severe in the uplink, because of the multipath fading of the wireless channel. A Hammerstein type decision feedback equalizer is described for the fiber wireless uplink, that compensates for nonlinear distortion of the ROF link as well as linear dispersion of the wireless channel. Since the linear and nonlinear parts of the receiver are separated, tracking the fast changing wireless channel is virtually independent of compensating for the relatively static nonlinearity. Analytical results show that the receiver provides excellent compensation with notably less complexity.

Abstract: A method of managing a free-space optical network includes monitoring environmental and weather conditions in the vicinity of one or more free-space optical links in the network. Data is gathered by environmental condition instruments, such as visibility meters, and is used to assess whether atmospheric conditions have deteriorated to the point where operation of one or more free-space links might be in jeopardy. If data from an environmental condition instrument falls below a predetermined level, network data traffic is routed over an alternate communication path, which may include radio frequency (RF) paths, fiber optic cables, wire cables, or other free-space links.

Abstract: The present invention provides an apparatus and a method for improved connectivity in wireless optical networks. Therefore at least two or more receiving units are used which receive an infrared signal and convert it to a digital signal. The digital signals represent data in the form of frames whereby each frame comprises at least a data field and a header field containing a preamble. A selector determines a measure related to the signal-to-noise ratio of the preamble and compares the measures in order to select the best suited signal for further processing.

Abstract: A free space optical interconnect system tolerant to misalignments and utilizing redundant elements of a transmitter and/or a receiver is provided. The elements are arranged into clusters, the number of clusters being redundant, and the number of elements in each cluster being sufficient to accommodate the number of data channels to be transmitted. The system also includes means for identifying misalignments between the transmitter and the corresponding receiver, including means for providing feedback between the transmitter and the receiver regarding the misalignment, and means for re-routing data from the cluster which is misaligned to the redundant cluster which thus redirects data to/from the correct physical location. Preferably, the elements are arranged into one-dimensional or two-dimensional arrays, the elements of the transmitter being optical emitters or optical modulators. Uni-direction and bi-directional link systems are implemented in various embodiments of the invention.

Abstract: A variable beam divergence FSO optical transmitter is described, as well as a method for altering the transmission power being radiated in a telescope for laser on air telecommunications systems. The method calls for the transmission of a very wide angle of the laser beam, in any case sufficient to ensure the quality of the link, when the level of atmospheric attenuation is at a minimum (good visibility conditions) and for a reduction of the beam, in a linear way, in order to increase the density of the power transmitted when visibility becomes poor (increase in atmospheric attenuation due to mist or fog). To increase or decrease the divergence of the beam, the distance between the source of light and the lens is altered in a suitable manner. After evaluating the extent of the variation due to atmospheric attenuation, arrangements are made to alter to a suitable extent the angle of the laser beam that is radiated.

Abstract: The present invention provides an apparatus and method for free space optical communication. The apparatus and method provide a free-space optical communication. The apparatus can include a link head configured to provide optical communication, a microroom cover positioned about and encasing the link head and a flexure support. The flexure support is secured at a first end with the microroom cover and extends away from the microroom cover, and is further secured at a second end with a structure, wherein the flexure support is configured to flex from a first position when a force is applied to the microroom cover. The present invention optically aligns a first and second free-space optical communication apparatuses. When a force is received on the first communication apparatus a portion of the first apparatus tilts to maintain the optical alignment between the first and second communication apparatuses.

Abstract: The present invention provides an algorithm for partitioning a portion of a load between a FSOW link and a RF link in order to maintain a FSOW link. By having the ability to adjust the load between a FSOW and RF wireless link during inclement weather, the ability to maintain the FSOW link is significantly increased. The algorithm of the present invention uses the BER to determine the current atmospheric attenuation and whether or not a percentage of the load is to be partitioned to the RF link. Using the BER to determine the actual atmospheric attenuation provides a better characterization of the link status, than other techniques such as the difference between the transmitted and received power. Once such a determination is made, a control circuit is used to partition a percentage of the load from the FSOW link onto the RF link.

Abstract: A free space optical communication system is disclosed whereby a transmit telescope and a receive telescope are aligned such that the point of maximum power of the received light beam is incident upon the optical fiber located at a specific point on the focal plane of the receive telescope. Such incidence is achieved by causing the transmitted beam to diverge by moving the transmit optical fiber to a point in front of the focal plane of the transmit telescope until at least a portion of the beam is incident upon the receive optical fiber. The transmit telescope and/or the receive telescope (or, alternatively, only the respective optical fibers of those telescopes) are then moved such that the point of maximum received power for that degree of divergence is incident upon the receive optical fiber.

Abstract: A bridge and roll method for doing an in-service switch (less than 50 ms) from one set of inputs and outputs on a primary photonic switch to another set of inputs and outputs on the same or a secondary photonic switch. The bridge and roll method facilitates maintenance, repairs and upgrades on the primary photonic switch. The bridge and roll method may be reversed in order to restore the original inputs and outputs on the primary photonic switch after maintenance, repairs or upgrades have been performed. The invention also provides a method for consolidating multiple wavelengths or multiple bands into single fibers.

Abstract: A free space optical communication system is disclosed whereby the received power at the receive optical fiber is reduced by adjusting the transmitted light beam and/or the receive optical fiber with respect to each other when a specified power threshold is exceeded. This reduction in received power is achieved by either increasing the cross section of the transmitted beam relative to the receive telescope or, alternatively, moving the receive optical fiber and thereby enlarge the cross section of the received beam incident upon the receive optical fiber.

Abstract: A laser-radar receiver comprising an array of optical fibres, wherein the opposite ends of the optical fibres are connected to at least one electromagnetic radiation detector, each of the optical fibres having differing physical characteristics which result in known delays in the transmission time of pulsed electromagnetic radiation.

Abstract: A method and apparatus for conditioning a wireless data communication path for the transmission of a signal wave are presented. The apparatus comprises a conditioning wave transmitter positioned to transmit a conditioning wave along at least a portion of the wireless data communication path. The conditioning wave forms a conditioning envelope about the data communication path. The wavelength of the conditioning wave is selected to remove undesirable particles from the wireless data communication path. As a result, the wireless data communication path is conditioned to provide for improved data communication. The conditioning wave may be transmitted co-, counter-, or bi-directionally with respect to the signal wave, and may form a second data channel.